Coffee whiteners have been traditionally of the liquid or powdered type. In recent years coffee whiteners in the frozen state have been marketed with some success, particularly in view of the public acceptance accorded to frozen foods for their convenience in handling and storage.
An especially serious problem has been the tendency of frozen coffee whiteners to separate or destabilize on thawing and refreezing. This phase separation or emulsion breakdown was most noticeable with pareve compositions, i.e., those employing ingredients of non-animal source such as all vegetable fats and proteins. Often, directions on pareve frozen coffee whiteners instructed the user to thaw the contents and shake well prior to use. On the first freeze-thaw cycle the emulsion breakdown was generally not total and vigorous shaking could be sufficient to effect dispersion or suspension and thus minimize the phase separation. On refreeze and rethaw, however, shaking in most any form was not sufficient to stabilize the emulsion for any reasonable period of time, thereby rendering the use of such liquid coffee whitener undesirable. Thus freeze-thaw stability would appear to be a very significant property. An inherent property of such coffee whitener compositions is the ability to whiten the dark coffee. A less noticeable problem is insufficient whitening property which could be due to minor emulsion phase breakdown.